A heads up display, also referred to as a head-up display system, includes a projector 10 which projects an image to be displayed towards a windshield glass 20, such that a driver can clearly see important information without the need of lowering his/her head, as shown in FIG. 1.
At present, information projected by a heads up digital display in a vehicle is mostly presented in green and orange colors, where the colors are relatively monotonous and cannot change. During actual travel, however, environment in the front is constantly changing, and when traveling in different environments, different colors will appear in the driver's field of vision, resulting in different background colors appearing on the heads up display. For example, a display background in a forest is green, and a background color in a desert is dark yellow. Thus, when a color of the environment is the same as or similar to a color of displayed information, it is very difficult for the driver to see the displayed information.